Ballistics labs within the FBI and law enforcement often use ballistics gel to test wound penetration. They use a special ordnance gelatin powder to make the gel to specific standards under carefully controlled conditions, and it is then calibrated for accuracy. We also wanted to use some ballistics gel for our Cheney Gunshot Experiment. We lacked the time or the facilities to prepare the gel to FBI standards, but we managed to whip up a reasonable homemade version in our kitchen.
We got our basic recipe and instructions by consulting a few different websites dealing with ballistics and firearms. Tactical Works has basic how to with clear photographs, and Firearms Tactical has more detailed step-by-step instructions. We used a simplified procedure from the SteyrScout.org site. Ideally we would have used gelatin powder made specifically for ballistics use, which is manufactured by Kind & Knox. However, the powder has to be special ordered in bulk and is expensive. We opted for two 8 oz. boxes of plain Knox gelatin off the supermarket shelf, which set us back about $8 each.
We used a basic formula of one pound of gelatin powder to one gallon of water. We mixed our gelatin in two batches using 8 oz. of powder and 2 quarts of water. After measuring out the cold water, we added the gelatin powder all at once. We stirred the powder in carefully, trying to moisten all of the granules without adding too much air. The mixture was the consistency of thick grits.
We set the gel mixture in the refrigerator to chill and hydrate (a process known as “blooming”) for two hours. We set the gelatin over a pan of water and heated it until it melted. A candy thermometer was used to make sure the gelatin mixture didn’t get hotter than 130 degrees. During the melting process, we stirred carefully to minimize air getting trapped in the gelatin.
The professionals use specially constructed 6” x 6” x 16” molds coated inside with silicone spray for easy release. We used 32 oz. Glad Ware containers and non-stick cooking spray. The gel was set to chill in the refrigerator for 36 hours before use. We carried it to the testing site in insulated containers and unmolded it before testing. Each of the blocks was cut in half, for a total of four blocks measuring about 7.5cm x 12 cm x 13.5 cm. If used in a clean setting, like a lab, blocks of ballistics gel can be recycled by melting them down and remolding them. However, ours got too full of dirt and wood splinters to be reclaimed.
Other experiments:
What is the Ultimate Jello-O Shot?
How Many Condoms Can You Wear at Once?
The Cheney Shotgun Experiment
Can Viagra keep flowers from wilting?